Communication networks, such as, for example, wireless networks that utilize IS-41 rely heavily upon accurate mobility data, which may refer to data used for locating a mobile subscriber within a network at a particular time. In order to deliver services such as, for example, call delivery and short message services (“SMS”) delivery, IS-41 based networks rely upon this information, which is typically stored in a home location register (“HLR”) and a visited location register (“VLR”). The HLR and VLR form the mobility management substrate of IS-41 network and accordingly, their function, malfunction, and normal (customizable) performance within the network are the basis for the accuracy of the mobility data.
As pointed out by the inventor, in a fixed network location, address and routing information are relatively static and methods for routing well established. Robert Todd Worrall, Development of a Supplementary Mobile Location Information Capability for Cellular and PCS Networks (2004) (unpublished, PH.D. candidate's report for peer review only). This is not the case in a mobile environment, however. Id. In a mobile environment, artifacts of mobility affect elements within the mobile environment. Id. Accordingly, having accurate mobility data is essential for a healthy network environment.
Unfortunately, analytical data show that mobility data within the HLR and VLR fail to reach high level of accuracy and consistency. Id. Inaccurate or conflicting records at HLR and VLR impair functions of IS-41 networks. For example, inaccurate information about a location of a mobile device in a network can have a negative impact on services and applications, diminishing the overall performance of the network. Id. To illustrate further, assume that one mobile subscriber (originating) attempts to reach out to another mobile subscriber (destination) by placing a call thereto. In a large communication network, it is not affordable to send the signal generated by the phone call to all networks nodes servicing all mobile devices in order to reach the intended mobile device. This simply overwhelms the system. So, the strategy is to maintain a database at the HLR that includes a current active location of the intended mobile device.
The network references this database, and based on the information stored therein, identifies the network node (e.g. one of the VLRs) servicing the intended mobile device and signals the identified network node (e.g., a VLR) to route the call to the current point of attachment of the mobile device. If the location registration information is incorrect for some reason, processing of the call may require additional signaling to other nodes or fail altogether. Hence, integrity of the data is quite important. Analytical studies show, however, that in a significant number of cases this database includes incorrect information about the location of the intended mobile device. That is, although the database indicates that a particular network node (e.g., VLR) services the intended mobile device, the particular network node (e.g., VLR) has no record for the intended mobile device and indeed does not service the intended mobile device. Therefore, the signaling generated in response to call from the originating mobile device consumes the system resources without having a meaningful result (e.g., without enabling the caller to connect to the destination mobile device).
Sometimes, there are good and valid reasons for such inconsistency between the records of HLR and VLR. For example, this inconsistency may exist for a short period of time in a border history cases as described in more detail below. However, the analytical studies show that there are some cases in which this inconsistency persists for a long period of time and are not suspected to be due to normal operating conditions. A classic example is the situation where a mobile device moves out of the service area of the overall network. In this case, there is no mechanism for the mobile device to signal the network that it is beyond range. Therefore, for at least some time, the network's location management system would understandably report such a mobile at its last known location. These inconsistencies can cause serious problems especially for applications, which are not designed with mobility in mind. For example, these inconsistencies will likely impair service performance and may go unnoticed until a faulted state of the system becomes obvious through service impairment.
Currently, there is no barometer which indicates the accuracy of mobility management data in HLR and VLR subsystems of the mobile communication network. Therefore, there is a need for a long-term and continuous methodology by which the mobile communication networks can measure the validity of mobility management data maintained by HLR and VLR. An operator may wish to utilize such information gathered in order to improve the “correctness” of mobile station location information and thus improve services delivery.